Method and means for working eccentrically-rotating parts.



APPLICATION FILED 13110.21, 190 7.

Patented June 1, 1909.

/v vE/Yf WI Tit 5856 that the shaft has inconveniences and difficulties.

" mechanical engineer,

.being especially UNITED STATES OFFICE,

. I I 0F.' SWEDEN.

' lo.all whom it may concern:

Be it known that I, ERNST THUNBI-me,

subject of Sweden, residing at Bofors, in the county of Wermland,

Sweden, have invented new and useful Improvements in Means for WorkingEccentricall'y-Rotating Parts, of which the following is a secification.

In wor g, for instance turning,.grinding and polishing eccentricallyrotating parts such as the cranks on crank shafts the method hithertoemployed has been either, been mounted in-a fixed position and the toolbeen rotated around the crank, or in most cases that on the endscf theshaft have been fixed pieces, that have been mounted between the centersof a lathe so that the axis ofthe crank has coincided with the axis ofsaid centers whereupon the crank has been turned or ground in the usualmanner. This, however, has caused several The whole shaft with exceptiononly of the crank being worked will rotate eccentrically with relationto the axis of the centers and thus cause an unevem motion and anextremely inconvenient strain on the machine, this strain importantin.working large and consequently heavy pieces. The eccentricallyrotating masses also will make the Working with a great speed diflicult,what otherwise would be possible with rapidly cutting steel. A thirdinconvenience is, that if several cranks are situated on the same shaftonly one ca-n be worked at a time. It

has also been proposed to ,mount the shaft being not quite'independentand positive but m some way controlled by the pin itself. This method,however, is unpractical, because only the shape of the pin, but not thecrank radius thus will be exactly determined by the tool. 1

According to the present invention, the shaft is mounted in-the lastmentioned way,

Specification of Letters Patent.

Application med December 21, Serial No. 407,660.

Fig. 2 in a reduced scale the Patented June 1 1909.

that is, ooaxiall -with the centers, and is worked by a too that ismoved in a'vertical and horizontal direction together with the crank-pm,but such motion 0 the tool in this case 1s fully and sitively determinedby a, special gear so t at the tool can work the rotating part (e. g.the pin) in a manner that is not dependent uponthe motion of the pm.

The method is illustrated in the accompanyi-ng drawin where it is shownas employed on a sha with two cranks.

Figure 1 illustrates the device for causing t e motion of the tool inelevation and shaft in position together with two working tools.

1 is the, shaft, 2 the cranks, 3 the centers of the lathe and 4 thetool-holders, each of which is mounted in the example illustrated in thesame way as a connecting-rod on two 4 plates 5, such plates having arotating motion so adapted, that the tool 6 will describe a circlearound the crank-pin during the rotation of the latter. The plates'areprovided withholes 7 or other securing devices on different distancesfrom the center, so that the. motion of the connecting-rods can bevaried according to the radius of the crank to be worked. The plates 5are driven by a suitable gearing from the same source of pfower as thelathe or grinding machine itsel 'Having now particularly described andascertained the nature of-my invention and in what manner the same isperformed, I declare that what I claim is:

1. In a device for turning the crank pins of crank shafts and the like,means for supporting the crankshaft, a pair of rotatable elements,arranged in line with each other and said crank pin, a bar, journalsconnecting the bar with said rotatable elements, a

tool carried by the end of the bar in contact with the crank pin to beturned, and means for rotating the crank shaft and said elementssynchronously.

2. In a device for turning the crank pins of crank shafts and the like,means for supporting thecrank shaft,.a pair of rotatable disks arrangedin line with each other and said crank pin, a bar, a pair of pivots carried by said bs-r, said hairin holes I In testimony whereof I havesigned my therein with which the pivots of the argue name to thisspecification in the presence of adalifed to engage whereby the position"of twi) subscribing witnesses.

the 7 :11- may be adjusted, a tool carried b ERNST THUN BERG.

5 the end of the bar] in contact with the cran Witnesses: I v pin, andmeans for rotatin the crank shaft JOHN EDBERG,

and said disks synchrono y. H. TmZANnER.

